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An '''operating systemOperating System (OS)''' is a set of basic software that allows [[computer]]s to perform basic tasks for people. It is responsible for displaying the graphics on screen and outputting sound to the speakers, controlling input from the mouse and keyboard, allowing [[hardware]] to work properly, interfacing with other computers on a [[network]], and storing and retrieving data. The most common desktop operating systems today are [[Microsoft Windows]], [[Apple Inc.|Apple's]] [[Mac OS X]], and [[GNU/Linux]]/. For mobile devices such as [[Smartphone]]s, [[Google]]'s [[Google Android|Android]] (a Linux derivative), and Apple's [[iOS]] are most common. The vast majority of web servers utilize Linux. Low-powered IoT devices typically run Linux, Android (a Linux derivative), or a basic RTOS such as [[BSDVxWorks]].

* The '''low-level system (such as [[BIOS]]''', UEFI, coreboot, or Libreboot) which handles manages all hardware related things. Often a computer has a BIOS or UEFI integrated within its hardware, though some operating systems such as [[Linux]] are independent of this BIOSthese proprietary systems.<ref>http://www.linux.com/base/ldp/howto/Linux-Init-HOWTO-5.html</ref>* The '''[[Operation system kernel|Kernel]]''', which handles all software related things operations and acts as a an interpreter between applications and the hardware.* The [[Computer shell|shell]] or User Interface - Software that draws forms, toolbars, menus, main task bar, typing commands for the computer to execute, etc. Shells typically provide a primitive programming capability, called scripting, such as DOS command scripts, JCL, DCL, and Windows script. Most operating systems designed for consumer use on desktop and mobile platforms, will include a graphical user interface, which presents the user with a point-and-click interface.* System programs that come packaged with the operating system, such as browsers, file backup/restore, sorting utilities, login/logout programs, etc.

== Sources Classifications =====General-purpose===General-purpose operating systems are designed to be flexible in what applications they can run, provide an interface, support multitasking, offer feature-laden file systems, and most of them support multiple users. These are the operating systems with which most people are familiar. ===Real-Time===Real-Time operating systems (RTOS) are designed to have minimal overhead so that they can respond immediately to events.<ref>http://ecomputernotes.com/fundamental/disk-operating-system/real-time-operating-systems</ref> As such, they tend to have no file system, or a simple file system optimized for speed. Real-time operating systems are used by embedded controllers in many devices, including industrial equipment, kitchen appliances, and automobiles. These controllers need to recognize task priority, and perform their primary function without delay when called upon. For example, the airbags in cars are controlled by an RTOS; every millisecond is critical in the processing speed for safety devices such as these.<ref>https://www.robomart.com/blog/real-time-operating-system-rtos/</ref><br />An RTOS that ran on the popular [[PDP-11]] minicomputers was RT-11. Today, [[VxWorks]] is the most popular RTOS. == Features ==General-purpose operating systems typically offer the following features:* Hardware Abstraction, which allows programs to make use of hardware without having to know about the specifics of any given hardware device. It is responsible for displaying the graphics on screen and outputting sound to the speakers, controlling input from the mouse and keyboard, and allowing [[hardware]] to work properly. Usually this is implemented in the [[BIOS]] or a separate HAL (Hardware Abstraction Layer).* Load programs from secondary stores into memory and execute them.* [[File System]]s, which handle storing and retrieving files stored on hard disks, USB drives, magnetic tapes, and CDROM/DVDROMs.* Security. Prevent unauthorized access to system resources.* Multiprocessing. Allow multiple programs to run simultaneously and share system resources.* Networking. Allows interfacing with other computers on a [[network]].* User interfaces, such as a [[Graphical user interface (computers)|Graphical User Interface]] (GUI), and system programs that provide users way of accessing hardware, files, programs, processes, and networks. ==Popular or Historic Operating Systems==* [[Google Android]]* [[iOS]] for [[iPhone]]/[[iPad]]* [[Mac OS]] for Mac* [[Microsoft Windows]]* [[Linux]] / [[Unix]] / [[BSD]]* [[VxWorks]]* [[MS DOS]] ==See also==* [[Apple Computer]]* [[Computer crime|Computer Crime]] and [[Cyberwarfare]]* [[Encryption]] ==References=={{Reflistreflist}} ==External links==*[https://www.kernel.org/ The Linux Kernel Archives]*[http://www.linux-foundation.org/en/Main_Page The Linux Foundation]

[[Category:TechnologyOperating Systems]]